The mythical Unicorns of Wall Street apparently had a very good Month in October after seeing a lot of their value disappear in September, at least according to fund manager Fidelity.

Keep in mind that Fidelity publishes their monthly portfolio holding listings with a one-month lag, so given the volatility of the valuations of Unicorns, the current values of the fast-growing firms can be quite a bit higher or lower than the latest data. On Monday of this week, however, Fortune was allowed to review data through the end of October for the $20.8 billion Fidelity Blue Chip Growth Fund and the $40 billion Fidelity Growth Company Fund (where Unicorn shares are held).

The October data showed that many Unicorns had bounced back significantly from the September lows, but the markups in value still leave Fidelity behind o its original investment in several cases.

Fidelity notes that an internal Fair Value Committee works together using common industry metrics to determine the current price for each security.

The methods used to value these new and often industry-disruptive firms are, however, of limited accuracy. As reported by ValueWalk, valuation of Unicorns really boils down to the use of “comparables” and there are none.

Mutual Funds Unicorns

Details on October valuations for Unicorns

Mobile messaging firm Snapchat enjoyed a mark up in the value of its Series F shares by 14.65% between the end of September and the end of October. Despite the almost 15% increase, however, Fidelity is still in the red on paper by 14.43%. The value of file-sharing and data storage company Dropbox moved up by 4.66% during October, close to 45.8% over cost, but still around 16% below Fidelity’s carrying value as of June 1st. Biotech Gensight Biologics was up 61.7% for the month, and is now valued at 62.7% over cost. Nutanix increased 22.73% for the month, and now stands at 31.84% above cost. Roku (multiple share classes) was up around 34% up for the month, with the Series F up 67.86% over cost and Series G 17% over cost. HR SAAS firm Zenefits increased  2.05% for the month, but is still on Fidelity’s books at 46.94% below cost.

The biggest loser of the month was Blue Bottle Coffee, whose Series C shares saw their value decrease by 28.7% during the month, dropping it to a whopping 59.6% below what Fidelity paid less than six months ago. Delphix, which develops big data management software, was also marked down 42.93% in October.